The present invention relates to a microwave plasma source which effects plasma etching and plasma oxidizing for semiconductor processing technology, surface treatment technology, etc.
Hereinbelow, a conventional magnetized microwave plasma etching apparatus (Japanese Patent Publication No. 56-37311) will be described.
FIG. 5 is a schematic diagram showing general construction of a conventional microwave plasma etching apparatus. Referring to FIG. 5, microwaves of a frequency of 2.45 GHz, generated by a magnetron 2, are is fed into a bell jar 1 made of quartz via a waveguide 3. In the bell jar 1, a magnetic field intensity of 875 G is applied to the microwave field of a frequency of 2.45 GHz by an external coil 4 so as to satisfy the ECR (Electron Cyclotron resonance) condition. As a reaction gas, SF.sub.6 or the like is introduced into the bell jar 1 through a gas inlet port 5. Within the bell jar 1, there are provided a substrate holder 6 and a substrate 7 disposed thereon. The bell jar 1 is installed on an evacuation chamber 8.
With respect to a microwave plasma etching apparatus constituted as described above, the operation thereof will be described with reference to the accompanying drawings. Using SF.sub.6 as a reaction gas, a plasma 9 is generated in the bell jar 1 within a pressure range of 10.sup.-4 to 10.sup.-3 Torr. In this case, a voltage RF (AC: 13.56 MHz), is applied to the substrate holder 6. Then, ions in the plasma 9 impinge on the surface of the silicon substrate 7 to achieve an etching due to an absorbed fluorine radical.
However, in the conventional microwave plasma source of such a construction, since a coil is employed to generate a magnetic field, the apparatus becomes bulky. Furthermore, there has been a disadvantage in that since part of the waveguide is used as a discharge domain, the sectional area and uniformity of the plasma are limited.